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Environmental stress is the main cause of the decline of species diversity in low-productive fen meadows in the Netherlands. Attempts to restore species diverse fen meadows e.g. by sod cutting frequently fail. We supposed that unsuccessful efforts are due to ignoring the impact of environmental stress on the performance of soil biota, which play a key role in N-immobilization and keeping available-N for primary production low. We investigated both pristine and degraded natural sites and successfully and unsuccessfully restored sites of poor and rich fen meadows. We determined plant species composition, soil chemical properties, N-pools in soil biota, N-mineralization rates, and N-fluxes. In pristine rich and poor fen meadows, mineral-N was poorly available for primary production due to a strong N-immobilization by soil biota. Annual N-immobilization fluxes exceeded by far the annual N-harvest by primary production. N-immobilization in pristine fens was higher than in degraded fens. In successfully restored rich fens, net N-mineralization was lower and N-immobilization higher than in the unsuccessful category. From our results, we derived the hypothesis that in degraded or in unsuccessfully restored fens the soils internal N-balance shifted from N-immobilization to net N-mineralization, favoring biomass production but disadvantaging plant species diversity. N-retention driven by an active N-immobilizing soil biological community, is likely a decisive process for successful recovery of plant species diversity in low productive fen meadows. We recommend that restoration techniques should stimulate a functionally diverse soil fauna, as this may enhance the storage of available nutrients in the soil food web.

This report presents the findings of quick surveys in three declining calcareous rich fens in the Slovak Republic to understand their origin and present state. Hypotheses were generated for further elaborated research as a base for restoration measures. Distinct sites along cross-sections were investigated by augering, soil sampling, making vegetation relevées and measuring temperatures and electric conductivities in peat profiles. Soil samples were collected for chemical analyses. Comparable processes and patterns were observed in the fens. The distribution patterns of the plant communities were strictly related to hydrological and pedological factors. The fens developed as flow-through-systems, with alternating cold discharge and warm recharge zones. Clear layers of calcite, pyrite and iron oxides alternated with organic layers in the discharge zones. Trophic levels of plant communities increased from the discharge to the recharge zones and were distinguished by distinct humus forms. Hardly any evidence was got for Fe- or Ca-bound inorganic P to explain low productivity at calcareous discharge sites, compared to recharge sites. Extremely low C/N and C/P ratio's suggested P and N immobilization by humification in these environments.

Ecohydrological systems analysis considers the soil to be the result of the interaction between regional hydrological processes and soil-forming rocks. Regional hydrological factors determine the development of the ecosystem, affecting the cycle of nutrients. Ecological and hydrological criteria are used for different mapped features of land at the level of physiotopes in order to model occurring processes. Dynamic models are also used to evaluate the change in the ecological quality of land and the response of surface vegetation to the regulation of the water regime. Recommended in the practice of ecological land evaluation are the so-called certificates of objects, which are based on data obtained from model calculations.

Soil maps are frequently used to evluate perspectives for nature restoration in scenarios of rural land use planning. Hydrological factors are decisive criteria at the higher levels of the Soil Classification System of the Netherlands. A case study atthe Wildenborch estate showed that traditional soil maps may give information on fossil hydrological conditions. Features of the humus form profiles provide actual information on the base and nutrient statuses of soils, being dependent on the hydrological factor. Humus form profiles must be incorporated in ecological land inventory.